AbdElMonem M. El-Sharkawy1, Di Qian, 1,2, Paul A. Bottomley1,2, William A. Edelstein1
1Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University, Baltimore, MD, United States; 2Electrical and Computer Enginnering, Johns Hopkins University, Baltimore, MD, United States
Accurate measurements of RF power deposition are central to safe MRI operation, especially at higher fields. We have characterized the losses in the body coil, cables, filter box, transmit-switch and quadrature hybrid. We find that transmit chain and body coil losses are such that the power reaching the patient is < 50% of the power supplied by the transmitter. Measured power deposition in four subjects of different body mass indices varied from 46-83% of the scanner estimated power deposition. This indicates that scanner estimates are not accurate indicators of MRI RF exposure.